Suction cleaner and dust receptacle therefor



Sept. 11, 1951 E. ANDERSON 2,567,171

SUCTION CLEANER AND DUST RECEPTACLE THEREFOR Filed April 4, 1947 3 Sheets-Sheet 1 INVENTOR. EMIL ANDERSON Sept. 11, 1951 E. ANDERSON 2,567,171

SUCTION CLEANER AND DUST RECEPTACLE THEREFOR Filed April 4, 1947 5 Sheets-Sheet 2 INVENTOR. EMIL ANDERSON ATTORN Sept. 11, 195-1 E. ANDE-RSON 2,567,171

SUCTION CLEANER AND DUST RECEPTACLE THEREFOR Filed April 4, 1947 5 Sheets-Sheet 5 [N VEN TOR.

u EMIL ANDERSON BY A 673 ATTO NEY. 7

Patented Sept. 11, 1951 SUCTION CLEANER AND DUST RECEPTACLE THEREFOR Emil Anderson, Briarcliff Manor, N. Y., assignor to Electrolux Corporation, Old Greenwich, Conn., a corporation of Delaware Application April 4, 1947, Serial No. 739,416

15 Claims.

This invention relates to suction cleaners, dust receptacles therefor, and closure structures and apparatus for such receptacles. While certain features of the broad inventive concept are widely applicable to various structures the invention'is more particularly concerned with suction cleaners of the cylinder type in which a floor supported housing encases a motor-fan unit and a dust separating and retaining receptacle. A flexible hose is usually provided to which cleaning attachments are applied and through which dust-laden air is drawn into the housing, through the separating and retaining receptacle and is discharged as clean air.

It is among the primary objects of the invention to pIOVide a novel, simple and improved organization of the character set forth.

Another general object of the invention is to provide for use in combination with such an organization a novel and improved dust receptacle.

A further generic object of the present invention is to provide means for closing the dust receptacle whereby it may be removed from the housing as a closed container from which accumulated dust and dirt may not be accidentally displaced.

In carrying out the inventive concepts above enumerated other features have been incorporated, one such feature being automatic actuation of the receptacle closing mechanism by operation of a closure member for the receptacle chamber of the housing.

Another object is to provide a receptacle the mouth of which may be readily closed and se-' cured in closed position so as to preclude accidental discharge of dust or dirt when the receptacle is removed from the housing and thereafter transported to a place of disposal.

, A further object of the invention is to provide a structure whereby the dust receptacle will be presented for convenient manipulation by the operator when the receptacle chamber is opened.

A further object of the invention is to provide an organization which will be fully automatic in operation so that in response to a predetermined drop in cleaning efficiency the receptacle chamber will be opened, the receptacle mouth closed and the receptacle positioned ready for removal all automatically and as an incident to a predetermined change in the efiiciency of the device.

Numerous other objects and features of the present invention will be apparent from further consideration of the invention as set forth in the following specification and depicted in the accompanying drawings, in which;

Fig. 1 is a side elevation partly in section of one embodiment of the invention showing the receptacle chamber closed;

Fig. 2 is a detailed side elevation of one end structure of the assembly with the receptacle chamber partially opened;

Fig. 3 is a similar view showing the receptacle chamber fully opened;

Fig. 4 is a front end elevation of the receptacle in dust receiving position;

Fig. 5 is a detailed section through the securing means shown in Fig. 4 when the receptacle is in closed position;

Fig. 6 is a view similar to Fig. 4 of a modified form of the receptacle;

Fig. 'l is a view similar to Fig. 5 of that form of the receptacle shown in Fig. 6, and

Fig. 8 is cross-sectional view taken along the line 8-8 of Fig. 1.

That form of the invention forming the subject matter of the present application may be broadly defined as comprising a housing having a receptacle chamber which receives a dust receptacle and which is provided with a cover for the receptacle chamber of the housing. Means are provided for latching the cover in closed position and for automatically releasing the latch as a result of variations of the cleaning efficiency of the dust separating and retaining receptacle. The receptacle is provided with a foldable end structure, portions of which may be brought together to form a closure for the receptacle and means are provided for retaining such portions in contact to retain the receptacle in closed position. Means are'also provided for automatically causing closing movement of such portions preferably as an incident to the opening of the chamber cover. This is accomplished by a lever mechanism by which pivotal movement of the cover actuates receptacle engaging arms which move the portions in hinged fashion and cause the interengagement of securing elements to retain the receptacle closed. An important feature of the present construction also resides in the fact that such movement leaves the receptacle in a position extending outwardly from the chamber so that it may be readily grasped to remove the receptacle for disposal.

Referring more particularly to the drawings, numeral It] indicates the housing which in that form of the invention elected as illustrative of the broad inventive concept is of substantially cylindrical form being adapted to be supported horizontally on a floor or like surface. Casters it may be provided to permit ease in movement of the housing over such surface. The housing It is preferably provided with a vertically transverse apertured bulkhead l2 dividing the housing into a rear motor-fan chamber I3 and a forward dust separating and retaining receptacle cham ber M. A motor-fan unit is mounted in he chamber 13 for producing a flow of air through the chamber l4 and the receptacle mounted therein the air being adapted to be exhausted from the chamber |5 through side louvers i5.

It will be understood that the invention is not concerned with the particular structure or mounting of the motor-fan unit i5 nor is the invention limited to the use of side louvers i5 which if desired, may be supplemented by or sub stituted by a rear exhaust port I! to which a hose may be attached should it be desired to use the structure as a blower.

Forwardly of the apertured bulkhead l2 there is mounted within the compartment M a dust separating and retaining receptacle generally indicated by the numeral IS in Fig. 1, the structure and mounting of the receptacle l8 being hereinafter referred to in detail. The forward end of the housing 10 and therefore the forward end of the chamber l4 terminates in an open end which is normally closed by an end cover l9 which is pivotally mounted to the top of the housing H) by a hinged connection including a transversely extending pintle 2B, which is fixed to the cover for movement therewith, a spring 2! being arranged to normally urge the cover to raised or opened position. The cover is retained in closed position against the tension of the spring 2| by a latch member 22.

Air is admitted through the cover member to the receptacle 3 through a U-shaped passage 23 which when the cover is in closed position as in Fig. l is in alignment with and in sealing relation to a longitudinal passage 24. Passage 24 extends within the housing from the cover l9 to the rear end above the motor-fan unit where it engages a hose coupling 25. Removably associated with the hose coupling 25 is a cooperating hose coupling 26 carried by a suction hose 2'! to which cleaning attachments may be applied for the removal by suction of dirt, dust and other foreign matter from rugs, floors, walls, draperies, upholstery and like surfaces.

That form of the receptacle l8 which is elected as best illustrating the inventive concept pertaining thereto comprises a body 30 as more clearly shown inFigs. 4 and 6. The body 3!] is preferably formed of inexpensive flexible porous material such as paper or the like and constitutes a flexible bag body. By the choice of inexpensive material the receptacle may be manufactured at a price so low as to permit disposal of the receptacle with its contents without increasing the cost of cleaning to a prohibited extent. However, if a disposable receptacle is not desired a more durable and expensive body formed of porous cloth may be utilized, it being understood that the invention is not concerned with the material of the receptacle.

The body 3% as shown in Fig. 1 has a closed inner end which is normally positioned in proximity to the bulkhead l2, while the forward end of the receptacle body is secured to a pair of stiff end members 3| which are hinged together by a hinge strip 32, the hinge line intersecting a central aperture 33 formed by meeting recesses in the members 3| thereof. The combined end members 3| are substantially rectangular and are provided at their four corners with pairs of rangement being such that when the end members fold along the strip 32 the securing members 3G and of each pair interengage to secure the end members in flat juxtaposition, thus sealing the aperture 33 to preclude accidental displacement of accumulated dust and dirt therefrom.

In that form of the receptacle shown in Fig. 4 the end members 3| are shown as being formed of stiff metallic material and each securing element 35 is shown as a projection which may be stamped outwardly from such material, while each securing element 34 is a simple aperture positioned for registration with a projection 35 tions 35 may be projected through the apertures 1 35 to be secured therein by frictional engagement.

In that form of the inventions shown in Figs. 6 and 7 the end members 3| may be formed of a single sheet of relatively stiff material such as cardboard weakened to form a fold line 32. The upper securing elements 38 of this construction are male elements of snap fasteners, the female elements 39 being mounted on the lower corners of the end member 3| so that when in folded position as shown in Fig. 7 the elements of the snap fastener will be engaged to secure the bag mouth in closed position.

As shown in Figs. 1 and 8 the receptacle when inserted has both sections of the end lying in a common plane transversely of the receptacle chamber. The end of the chamber is provided with an encircling receptacle seat and sealing rim 4!! which is rabbeted as at 4| to receive and seat the outer projecting flange of the end member.

The member ii constitutes an apertured end wall for casing I5 through which the tube 24 extends. On either side of the body 30 of the receptacle the member 40 is slotted to permit pivotal movement therethrough of the receptacle manipulating arms as hereinafter disclosed. From Fig. 8 it will be noted that the rabbet 4| surrounding the central aperture of the member 46 is, at the sides, beyond the slots and that the stiff end member of the receptacle extends at its sides beyond the body 30 to overlap the slots and to be received and sealed in the side rabbets 4|.

For moving the companion sections of the end 3| of the receptacle [8 along the hinge strip 32 there is mounted at the mouth portion of the dust receptacle chamber l4, upper and lower closure arms 50 and 5| respectively, one pair being provided at each side of the chamber opening as shown in Fig. 8. The closure arms have elongated straight free ends which terminate in forwardly turned inner ends 52, the terminal portions of the inner ends 52 of each pair being mounted for pivotal movement on fixed pivot pins 53. At the juncture of the straight free ends of the arms and their forwardly turned ends 52 there is provided an operating link 54 for each arm. The links 54 are substantially curved and are pivotally joined to the arms-by connector pins 55. Each pair of operators 54 are joined at their opposite ends and to the midsection of an arm 56 by a pintle 51, the connection being such as to permit independent pivotal movement of the operators with respect to each other and pivotal movement of the arm 56 with respect to the operators. The arrangement also provides for bodily movement of the operators with pivotal movement of the arm 56, which bodily movement will produce pivotal movement of the arms 55 and 5|. The arm 56 has a lower straight section the extremity of which is mounted on a fixed pivot point 58 and intermediate its ends at the point of engagement of the pintle 51 the arm is bentforwardly and terminates in a rear inclined surface 69 and a straight forward front terminal surface 6|.

For operating the arm 56 by and with movements of the cover l9 there is provided a pair of operating arms 62, the upper ends of which are fixedly secured to the pintle 29 which is mounted for rotary movement with the cover IS. The lower portion of each arm 62 is provided with an offset 64 which is. adapted to engage the arm 56 to bring about itsactuation with the cover l9. As noted in Figure l the normal positionof the operating arms 62 when the cover is in closed position is at a rear inclination with respect to a vertical plane through the machine and in such position the offset 64 is in contact with the rear inclined surface 69. Tension is constantly appliedto the arm56 to urge it towards clockwise rotation on its pivot 58' by a spring 65, the spring 65 being anchored as at 66 to the lower end of a stop arm 61, the upper end of which is pivoted at a fixedpoint 68p Intermediate the ends of arm 61 there is connected a stop link 69 which is guided for rectilinear movement by a fixed pin 19 which extends through a guide slot H in the link 69, the arrangement being such that clockwise movement of the arm 56- in response to tension of the spring 65 is terminated by the striking of the central portion of the arm 56 with the forward end of the link 69 at which time the forces of the spring 65 are counteracted by the pressure from the arm 56 to the link 69. The arrangement, however, permits a further clockwise movement of the link 56 under the influence of offset 64 when the offset forces the link to move in such clockwise direction by engagement of the offset with the forward straight front-6| of the link 56 while the cover is being closed.

4 When the cover I9 is released from its closed position shown in Figure 1 it will move upwardly and outwardly rotating with the pintle 29 to the position shown in Figure 2, during which time the offset 64 moves across the rear inclined surface 69 of the arm 56 rocking the arm in counterclockwise direction against the tension of spring 65. Such movement produces a forward arcuate movement of the pintle 51 which movement imparts a bodily forward movement to the links 54 which through pivoted engagement with the op erators 59 and 5| cause them to rotate in mutually opposite directions about their fixed pivot pins 53. Continued upward movement of the cover continues such mutualopposite and pivotal movement of the arms 59 and 5| and since each pair of arms is'positioned on opposite sides of the members 3| of the receptacle l8 and since the center portion of the end is frictionally retained by central spring urged ball 86 such movement of the arms 56 and 5| will cause the sections of the ends 3| to fold forwardly as shown in Figures 2 and 3, the final forward movement of the arms causing. the securing means 34 and 35 or 38 and 39 to engage to secure the bag mouth in closed position after withdrawal of the arms 59 and 5|.

Such, withdrawal of the arms is effected by the passage of the offset 64 over the ends of the arms 56. When the arms are disengaged, the springs 65 will move the arms in clockwise direction to retract the arms to the position shown in Figure 3, further movement of the arms being stopped by arm 56 contacting the end of link 69. As hereinbefore described, When'the cover is again closed the offset 64 strikes the surface 6| forcibly moving; the arm 56 further in clockwise direction beyond the position shown in Figures 1 and 3. This displaces link 69 to the right and pivots arm 61 counterclockwise, as viewed in Fig. 8, thus increasing the tension of spring 65 until the offset 64 passes over the ends of the arms 56, whereupon the spring 65 moves the arms 61 and 56 to the initial position shown in Fig. 1, the offset 64 thus being repositioned adjacent to the surface 69 of the arm 56 where it is ready for a new cycle of operation as shown in Figure 1.

As hereinbefore referred to the cover I9 is normally retained in closed position against the tension of the spring 2| by the catch 22. The catch 22 is pivoted to the casing as indicated at B9 and is adapted to be automatically actuated in response to variations in the efiiciency of the device by means of a solenoid 8| and link 92, the arrangement being such that when the solenoid is energized the link will be retracted to release the latch, moving it to the position shown in Figures 2 and 3. For controlling the energization of the solenoid 8| a'switch B3 is provided which is adapted for actuation by a Sylphon 94. When the receptacle is loaded with dirt, thus resisting the passage of air therethrough, the suction in the receptacle compartment l4 will increase thus expanding the Sylphon to close the switch 83 and energize the solenoid Bl. It will be understood however, that other control means may be provided with respect to which reference may be had to the copending application of Ferman C. Doughman, Serial No. 676,318 filed June 12, 1946. In the operation of the device during the normal cleaning cycle the parts are arranged as shown in Figure 1, the rigid end structure of the bag being seated within therabbet 4| of the member 49. With the cover closed the end of the tube 23 is extended through the aperture of the rigid end structure of the receptacle while the opposite end of the tube .23 'is in sealing engagement with the tube 24. With the parts in this position, upon energization of the motor by manipulation of the switch 25, air is drawn through the hose 2?, tubes 23 and 24 to pass into the receptacle |8 which filters out the, dust particles permitting theclean air to pass through the fan and to be exhausted through the louvers l6 or the outlet When the receptacle is loaded with dirt to a point where resistance to air flow is such as to impair efficiency, bellows; 84 is operated to close the switch 83 in the manner above described, thus energizing the solenoid and pivotally moving the catch 22, whereupon the spring 2| will open the cover moving it through the position shown in Figure 2 to the fully opened position shown in Figure 3. As the cover thus moves in clockwise direction with respect to Figures 1 through 3 the arm 62 will move with the cover and its pintle 29 in the same direction. Offset 64 of the arm 62 will engage the rear surface 69 of the arm 56, moving the arm 56 in counter-clockwise direction to move the links 54 forwardly,'thus rocking the arms 59 and 5| on their pivot 53, whereby the ends of the arms 50 and 5| engage the members 3| ofthe receptacle to hingedly move them toward each other; Opening movement of the cover will re tract tube 23 from the aperture 33 formed by the elements 3| and continued movement of the arms 59 and 5| will close the aperture 33. The final movement of the arms 59 and5| will cause en gagement ofthe securing means 34 and 35 'or 38 and39 so as to secure the elements in over lying. position and against accidental displacement from such position. In such movement of the arms- 50 and the central portion of the rigid end structure of the receptacle is restrained against forward movementwith the outer edges of the members 3| by detents 86 which are urged into end engaging position by springs 81 so as to preclude bodily forward movement of the re ceptacle as a consequence of the folding movement imparted by the arms 59 and 5|.

An important feature of the present invention is that when the elements 3! are folded to seal the receptacle they are moved forwardly from the vertical plane in which they stand during operation as shown in Figure l to extend horizontally forward of the mouth of the receptacle compartment i4 so as to present a convenient grasping portion indicated at 18 in Figure 3 by which the receptacle may be grasped for convenient withdrawal from the compartment.

When the dust-laden receptacle is removed from the compartment a new receptacle may be conveniently inserted with the edge portions of its elements 3| lying within the rabbet 4i and with its central portion resting behind the dearm 62 passes across the outer end of the arm 1:

56 which is pivotall moved in clockwise direction, such movement-being permitted by the arr'angement of the spring 65 and the link 59. At the conclusion of the closing movement the 01T- set passes over the link 56' which again resumes I the position indicated in Figure 1 by action of the spring 65; Such movement of the cover also cams the latch 22. to move on its pivot permitting the cover to take its proper position after which the latch returns to the securing position shown in' Figure 1 and the device is ready for another cycle of operation.

In considering the present invention it will be understood that the various features thereof may be individually used in different combinations other than that here shown and that the inventive concept may be carried out with numerous changes and modifications from the structure here shown without departure from the spirit or scope of the present invention as outlined in the appended claims.

What I claim is:

1. In a vacuum cleaner, a casing forming a dust receptacle chamber, a dust receptacle receivable in said chamber, said receptacle being formed with an inlet opening and a portion foldable to close said opening, a conduit engageable with said inlet opening, means for permanently and movably supporting said conduit from said casing independently of said opening so that the conduit is movable out of engagement with said opening, and structure operable by movement of said conduit out of engagement with said inlet opening for folding said portion to close the opening.

I 2. In a vacuum cleaner, a casing forming a dust receptacle chamber having an aperture, a dust receptacle insertable into and removable from said chamber through said aperture, said receptacle being formed with an inlet opening and a portion foldable to close said opening, and structure movably carried by said casing for foldto close said inlet opening and to render said 8-. receptacle accessible for removal from said chamber.

3. In a vacuum cleaner, a casing forming a dust receptacle chamber having anaperture, a dust receptacle insertable into and removable from said chamber through said aperture, said receptacle being formed with an inlet opening, and a portion foldable to close said opening, a cover member for said aperture movably supported by said casing, and structure operable by opening movement of said cover member for folding said portion to close said inlet opening;

4. In a vacuum cleaner, a casing forming a dust receptacle chamber having anaperture, a dust receptacle insertable into and removable from said chamberthrough said aperture, said receptacle being formed: with an inlet opening and a portion foldable to close said opening, a cover member for said aperture movably supported by said casing, a conduit carried by said cover member and engageable with said inlet opening when said cover is in closed position, said conduit being disengageable from said inlet opening by opening of said cover member, and structure operable by opening movement of said cover member for folding said portion to close said inlet opening.

5. In a vacuum cleaner, a casing forming a dust receptacle chamber, a dust receptacle receivable in said chamber, said receptacle including a member of relatively rigid material formed. with an inlet opening therein and having portions hinged together adjacent to said opening and including a bag-like member of flexible air pervious material secured to both of said portions, and structure movably carried by said casing for folding said hinged portions together to close said inlet opening.

6. In a vacuum cleaner, a casing forming a dust receptacle chamber, a dust receptacle re ceivable in said chamber, said receptacle including a member of relatively rigid material formed with an inlet opening thereinv and having portions hinged together adjacent to said opening, a pair of arms pivotally mounted in said casing and disposed adjacent to said member when said receptacle is received in said chamber, and means for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening.

7. In a vacuum cleaner, a casing forming a dust receptacle chamber, a dust receptaclereceivable in said chamber, said receptacle including a member of relatively rigid material formed with an inlet opening therein and having portions hinged together adjacent to said opening, a pair of arms pivotally mounted in said casing and disposed adjacent to said member when said receptacle is received in said chamber, means for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening, and resilient means stressed by the pivoting of said arms for returning the latter to their initial position.

8. In a vacuum cleaner, a casing forming a dust receptacle chamber having an aperture, a dust receptacle insertable into and removable from said chamber through said aperture, said receptacle including a plate of relatively rigid material formed with an inlet opening therein and having portions hinged together adjacent to said opening, a member pivoted to said casing and spanning said aperture for retaining said receptacle in said chamber with said plate in unfolded condition adjacent to said aperture, a pair of arms pivotally mounted in said casing and disposed adjacent to said plate when said receptacle is received in said chamber, and means operable by pivoting of said member away from said aperture for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening.

9. In a vacuum cleaner, a casing forming a dust receptacle chamber having an aperture, a dust receptacle insertable into and removable from said chamber through said aperture, said receptacle including a plate of relatively rigid material formed with an inlet opening therein and having portions hinged together adjacent to said opening, a member pivoted to said casing and spanning said aperture for retaining said receptacle in said chamber with said plate in unfolded condition adjacent to said aperture, a pair of arms pivotally mounted in said casing and disposed adjacent to said plate when said receptacle is received in said chamber, means operable by pivoting of said member away from said aperture for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening, and resilient means stressed by the pivoting of said arms for returning the latter to their initial position.

10. In a vacuum cleaner, a casing forming a dust receptacle chamber having an aperture, a dust receptacle insertable into and removable from said chamber through said aperture, said receptacle including a plate of relatively rigid material formed with an inlet opening therein and having portions hinged together adjacent to said opening, a member pivoted to said casing and spanning said aperture for retaining said receptacle in said chamber with said plate in unfolded condition adjacent to said aperture, a pair of arms pivotally mounted in said casing and disposed adjacent to said plate when said receptacle is received in said chamber, means operable in response to an increase in the amount of dust collected in said receptacle for pivoting said member away from said aperture, and means operable by th pivoting of said member for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening.

11. A dust receptacle for a vacuum cleaner comprising a relatively flexible bag-like body having an aperture, closure structure for said aperture including a pair of relatively rigid flat plate members hinged together and secured to said body, said structure being formed with an inlet opening adjacent to the hingedconnection between said plate members and said opening having dimensions substantially less than the dimensions of the plate members, said plate members being foldable together to close said inlet opening, and means on said plate members for retaining them in folded position.

12. A dust receptacle for a vacuum cleaner comprising a relatively flexible bag-like body having an aperture, closure structure for said aperture formed with a centrally located inlet opening, said structure including a pair of relatively rigid fiat plate members secured to said body and hinged together along a line intersecting said opening, said inlet opening being substantially smaller than said plate members, the plate members being foldable together to close said inlet opening, and means on said plate members for retaining them in folded position.

13. In a vacuum cleaner, a casing forming a dust receptacle chamber having an aperture, a dust receptacle insertable into and removable from said chamber through said aperture, said receptacle being formed with an inlet opening and a portion foldable to close said opening, a cover member for said aperture movably supported by said casing, means operable in response to an increase in the amount of dust collected in said receptacle for opening said cover, and structure operable by opening movement of said cover member for folding said portion to close said inlet opening.

14. In a vacuum cleaner, a casing forming a dust receptacle chamber, a dust receptacle receivable in said chamber, said receptacle including a member of relatively rigid material formed with an inlet opening therein and. having portions hinged together adjacent to said opening, a pair of arms pivotally mounted in said casing and disposed adjacent to said member when said receptacle is received in said chamber, and means responsive to an increase in the amount of dust collected in said receptacle for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening.

15. In a vacuum cleaner, a casing forming a dust receptacle chamber having an aperture, a dust receptacle insertable into and removable from said chamber through said aperture, saidreceptacle including a plate of relatively rigid material formed with an inlet opening therein and having portions hinged together adjacent to said opening, a member pivoted to said casing and spanning said aperture for retaining said receptacle in said chamber with said plate in unfolded condition adjacent to said aperture, a pair of arms pivotally mounted in said casing and disposed adjacent to said plate when said receptacle is received in said chamber, means operable in response to an increase in the amount of dust collected in said receptacle for pivoting said member away from said aperture, and means operable by pivoting of said member away from said aperture for pivoting said arms into engagement with said hinged portions for folding the latter together to close said inlet opening.

EMIL ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,018,417 Ford Feb. 27, 1912 1,254,188 Allen Jan. 22, 1918 1,654,921 Critelli Jan. 3, 1928 ,022,249 Lofgren Nov. 26, 1935 2,022,250 Lofgren Nov. 26, 1935 2,070,674 Muenter Feb. 16, 1937 2,152,745 Kloss Apr. 4, 1939 2,167,861 Zimmern Aug. 1, 1939 FOREIGN PATENTS Number Country Date 506,345 France May 28, 1920 569,575 France June 8, 1924 745,422 France Feb. 14, 1933 515,927 Germany Oct. 31, 1929 

